Characteristics of Si₃N₄/Si/n-GaAs metal-insulator-semiconductor interfaces grown on GaAs(111)B substrate

Interfacial properties of Al/Si₃N₄/Si/n-GaAs metal-insulator-semiconductor (MIS) capacitors grown on GaAs(111)B prepared with a combination of in situ molecular beam epitaxy and chemical vapor deposition techniques are presented. The density of the surface states in the high 10¹⁰ eV^-1 cm^-2 near the GaAs midgap for the GaAs grown at 575 and 625°C was obtained. The MIS structure with GaAs homoepitaxial layer grown at 625°C, showing smoother surface morphology than the surface grown at 575°C, exhibited small hysteresis which was as small as 30 mV under a field excursion of 1.5 MV/cm. The presence of a 1 MHz frequency response at 77 K requires that the traps be within 60 meV of the conduction band edge of GaAs and confirms the unpinned GaAs surface Fermi energy within GaAs band gap.